How would a four-tier traffic light travel system work?

The government is mulling over the introduction of a traffic light system for travel with countries labelled green, yellow, amber and red. Countries will be labelled depending on Covid case numbers and the system is seen as a substitute for the often chaotic travel corridors utilised in 2020. Professor Andrew Hayward of the University College of London suggested the idea during an interview with Radio 4’s Today Programme, saying that countries struggling with new variants could be designated as no-go areas or ‘red’ countries. And the system is now one of several being considered by the Global Travel Taskforce as a tool for unlocking international travel this summer. Here's how such a system would work. How would a traffic light system work? The system would allocate countries a colour depending on if they were safe to visit for a holiday during summer. According to The Telegraph, no travel restrictions would be attached to green countries. Those returning from yellow listed countries, however, would be required to present proof of testing and/or vaccination before entering the UK but would not be required to quarantine. Travel to and from an amber country would require a test within 7 hours of departure and arrival to and from the UK with travellers able to leave quarantine on the third day if they test negative. No entry would be permitted from red-list countries with limited exceptions. Why is it being considered? 2020’s travel corridor system often resulted in chaos with holidaymakers forced to rush home with 24 hours notice in order to avoid a lengthy quarantine period. It is hoped that a traffic light system would provide greater clarity to travellers while notifying travellers of changes to a country’s status farther in advance. There is also a growing belief that travel abroad needs to be curbed despite the Westminster Government once indicating that international holidays could resume from May 17. This increased caution is due to the increasingly likely threat of a third wave of coronavirus cases sweeping across continental Europe. Which countries will be assigned which colour? As Professor Hayward already indicated countries, such as South Africa and some South American countries, where strains resistant to the vaccine are prevalent would be allocated as red countries. Countries who have long had a grip of the pandemic would likely be provided ‘green’ status. This could include the likes of Australia, New Zealand and Singapore. It’s worth noting, however, that many of these countries are not welcoming tourists at present. Countries where the situation is improving such as Portugal and Iceland may also be listed as safe-to-visit destinations. Tourist hotspots such as France, Italy and Turkey could be deemed as amber, or even red destinations, due to the increasing threat of a third wave of infections and a struggling vaccine programme.